Collaborative Research: Spider Web Vibrations -- Active and Passive Detection

网络传播的振动是许多蜘蛛感官信息的主要来源。最著名的是，它们会告诉蜘蛛被困在网中的猎物的位置；网的振动也会传递来自潜在配偶的信号，并提醒蜘蛛注意自己捕食者的存在。这些捕食者中的一些反过来利用蛛网振动来发送误导信号，诱骗蜘蛛进入伏击，或者在其他蛛网干扰中“隐藏”它们的方法。因此，了解蛛网的几何形状和组成(由几种丝织网编织而成)如何影响这些线索的传递，对于了解蜘蛛的行为和生态具有重要作用。生物学家对这些现象进行了实验研究，例如，测量由不同几何形状引起的网络频率响应。对网络振动建模的关注要少得多，尽管这样的模型将提供额外的洞察力。例如，在频率响应研究中，实验者仅限于处理自然的网或去掉线的网，不能测试任意改变线模式或类型的效果，这将是理解网站设计的关键。这个项目将通过探索蜘蛛网的设计来填补这一空白，通过弦网络振动的计算模型来探索蜘蛛网的设计，并以新一代生物和人工构建的网的实验为支持。这项拟议工作的关键和更广泛的影响是让生物学家和其他没有动力系统专业知识的人可以使用复杂的现代振动模型。蜘蛛如何找到猎物是一个引人入胜的故事，将启发K-12年级的学生学习物理、数学、生物和工程之间的相互作用；PI将开发一个简化的“教学”版本的界面，将通过俄勒冈州立大学的中学推广计划和伯克利分会“扩展您的视野”，一个促进中学女孩进入STEM领域的组织分发。PI将特别调查网络的几何形状和组成如何影响蜘蛛用来定位和识别被困猎物的振动信号的传输。PI将把现代动力系统理论和实验技术应用于生物学研究中公认的需要，并通过这样做扩大对弦网络物理的理解。与前人在这方面的研究相比，该工作将首次明确和定量地考虑全幅振动能量路径，寻找振动响应中的非线性效应，并在实验上记录振动幅上各点的全程运动。这项拟议的工作也将是第一次定量研究“主动探测”行为的机制，在这种行为中，蜘蛛拔起或摇动它的网，以寻找其动态特性的变化，这将表明网中存在猎物或捕食动物。

Web-borne vibrations are the main source of many spiders' sensory information. Most famously, they inform spiders of the location of prey trapped in the web; web vibrations also carry signals from potential mates and alert spiders to the presence of their own predators. Some of these predators in turn exploit web vibrations to send misleading signals that trick spiders into ambushes or to "hide" their approach among other web disturbances. Understanding how web geometry and composition (webs are woven from several types of silk) affect transmission of these cues thus plays an important role in understanding spiders' behavior and ecology. Biologists have investigated these phenomena experimentally, for example, measuring web frequency responses resulting from different geometries. Much less attention has been directed to modeling web vibrations, despite the additional insight such models would provide. In the frequency response study, for instance, the experimenters were limited to working with natural webs or those with threads removed, and could not test the effects of arbitrarily altering thread patterns or types, which would be crucial for understanding web design. This project will fill this gap by exploring the design of spider webs through computational models for the vibration of string networks backed up by a new generation of experiments on biological and artificially-constructed webs. The key broader impact of the proposed work is making sophisticated modern vibration models available to biologists and others whose expertise is not in dynamical systems. How spiders find their prey is a compelling story and will inspire K-12 students with the interplay between physics, math, biology, and engineering; the PIs will develop a simplified 'teaching' version of the interface, to be distributed through Oregon State University's middle-school outreach program and the Berkeley Chapter of "Expanding your Horizons," an organization to promote the inclusion of middle school girls in STEM fields.In particular the PI will investigate how a web's geometry and composition affects the transmission of vibratory signals that spiders use to locate and identify trapped prey items. The PI will apply modern dynamical systems theory and experimental techniques to a recognized need in biological study, and in doing so expands understanding of the physics of networks of strings. Compared to previous research in this area, the proposed work will be the first to explicitly and quantitatively consider whole-web vibration energy pathways, look for nonlinear effects in the vibration response, and experimentally record the full motion of points in the vibrating web. The proposed work will also be the first study to quantitatively investigate the mechanics of "active probing" behavior, in which the spider plucks or shakes its web to look for changes in its dynamic properties, which would indicate the presence of a prey or predator animal in the web.